М (H2O) = 18
18 ---100%
16 -----х
х =88,89%
М (SiO2) = 60
60 ---100%
32 ------х
<span>х =53,3%</span>
CH3-C(CH3)=CH2+KMnO4+H2O= CH3-C(-CH3 вниз, -OH вверх)-CH2-OH + KOH + MnO2
А) Ca3P2 + 6<span>HCl </span>= 3CaCl2 + 2PH<span>3
</span>2PH3 + 4O2 =<span> P</span>2O5 + 3H2<span>O
</span>P2O5 + 6<span>NaOH </span>= 2Na3PO4 + 3H2O
б) FeO + CO = Fe + CO2
Fe + 2<span>HCl </span>=<span> FeCl</span>2 +<span> H</span><span>2
</span>FeCl2 + 2<span>NaOH </span>=<span> Fe(OH)</span>2 + 2<span>NaCl
</span>4Fe(OH)2 +<span> O</span>2 + 2H2<span>O </span>= 4Fe(OH)3
в) Na2<span>O </span>+ 2<span>HBr </span>= 2<span>NaBr </span>+<span> H</span>2<span>O
</span>2<span>NaBr </span>+<span> Cl</span>2 = 2<span>NaCl </span>+<span> Br</span><span>2
</span>NaCl +<span> AgNO</span>3 =<span> NaNO</span>3 +<span> AgCl</span>
г) C + O2 = CO2
CO2 + 2<span>NaOH </span>=<span> Na</span>2CO3 +<span> H</span>2<span>O
</span>Na2CO3 + 2HNO3 = 2NaNO3 +<span> H</span>2<span>O </span>+<span> CO</span><span>2</span>
Ответ:
N2Ca ( 2 Пишется маленькой)
<span>m(р-ра) = 100г m(соли)=100х0,2=20 г
W(соли)=20% m (р-ра 2)=100+20=120 г
добавили (w cоли)= 20\120х100%=16,67%
m( H2O )= 20 г
Найти (W) соли новом растворе </span>